The blades of chopper device of the type referred to above rotate with the associated rotor assembly at high speed within a cylindrical housing so that the cutting edges thereof come into close proximity to the inner surface of the housing to chop or comminute meat, or other product being chopped, as the product passes through the housing. In the course of normal operations, the cutting edges of the blades become dull and in time require sharpening. However, repeated sharpening of the blades results in removal of metal from the cutting edges and and noticeably increases the normal small spacing or clearance between the cutting edges of the blades and the inner surface of the cylindrical housing, thereby preventing proper comminution of the meat or other product. It has therefore been necessary with some chopper devices to frequently replace the blades even though the blades still include ample blade material for sharpening. Considering the large number of blades in a chopper, the cost of frequent replaclement is considerable. An example of an arrangement of this type is that disclosed in U.S. Pat. No. 2,742,937 (Herzer).
To overcome these problems, improved chopper blades have been provided which are pivotably connnected to the rotor in a manner such that the cutting edges thereof are centrifugally urged into close proximity to the inner surface of the cylindrical housing or bowl and wherein a stop pin is provided on the blades to ensure maintenance of a desired clearance between the cutting edges and the inner surface of the housing. A major advantage of this arrangement is that the blades can be sharpened although, as noted below, some reshaping of the blade is required when the blade is sharpened to maintain the desired clearance. Examples of such blade arrangements are disclosed in U.S. Pat. Nos. 3,030,993 (Schmook, Jr.); 3,215,535 (Schomook, Jr. et al), the disclosures of which are hereby incorporated by reference.
The chopper blades disclosed in these patents are pivoted at one inner ede and the stop referred to comprises a fixed pin or projection which is received in a recess or slot in the other inner edge of the blade, the recess forming a "ledge" or "heel" at one corner of the base of the blade. This "ledge" constitutes a projection or shoulder which engages the stop pin when the blade is pivoted and thus limits the pivoting movement of the blade so that the desired clearance is maintained.
While this arrangement provides marked advantages over the prior art and is more than adequate for its intended purposes, the arrangement suffers certain drawbacks. More specifically, the "heel" of the blades of such prior art devices is subject to breakage. This tendency to break increases as the blade is removed from time to time in the routine sharpening procedure referred to above, in that it is necessary to remove a small part of the blade in the portion of the heel which engages the stop pin so as to permit the blade to remain close to the wall of the bowl during the operation of the device and thus provide the appropriate comminuting action. This removal of material weakens the blade in an area where the blade is already weakest and thus increases the the chances of breakage.
Other patents which disclose devices which may be of possible interest insofar as the present invention is concerned include U.S. Pat. Nos. 14,926 (Plaisted), directed to a rotary hammer; 2,536,929 (Hammell), directed to a garbage grinder; 2,656,985 (Backlund et al), directed to a garbage disposal apparatus; and 2,822,138 (Oliver), directed to an impact crusher. The rotary hammer of the Plaisted patent includes blades which are attached to a hub and which each include a radial end having a flat surface that contacts an adjacent flat surface of the hub. During rotation of the hub, the blade pivots outwardly until the flat surface contact each other. In the impact crusher of the Oliver patent, hammers are pivotedly connected to a certral hub and swing outwardly from hub until a stop extending from the hammer contacts an abutment on the hub. The grinder of the Hammell and Backlund et at patents include hammers which swing to a substantially straight our (radial) position.